State-of-the-art survey of dissimilar metal joining by solid state welding

State-of-the-art of dissimilar metal joining by solid state diffusion bonding and roll and press welding, emphasizing stainless steel and aluminum allo

Effect of herd health management on the prevalence of Postpartum Dysgalaktie Syndrome (PPDS) and the treatment incidence

The Postpartum Dysgalaktie Syndrome (PPDS) also known as metritis agalactia mastitis (MMA), is considered the most common disease of the sow after farrowing. The reasons for PPDS are multifactorial and are to be found in the areas of management and hygiene, feeding, water supply and animal specific factors such as body condition and age of the sows. In this study a veterinary herd health management was carried out in 28 pig farms with PPDS, with the aim to reduce the PPDS prevalence and animal treatment incidence (TI). In 20 of 28 problem farms the PPDS-prevalence could be decreased from 37.4% (± 21.8%) to 24.5% (± 14.1%). The TI was not significantly reduced. The most effective procedures to reduce the PPDS-prevalence were the use of a prepartal transition feed, optimizing the PPDSdiagnostic and the use of nonsteroidal antiinflammatory drugs (NSAID) and oxytocin in the PPDS-treatment

Quantum and classical descriptions of a measuring apparatus

A measuring apparatus is described by quantum mechanics while it interacts with the quantum system under observation, and then it must be given a classical description so that the result of the measurement appears as objective reality. Alternatively, the apparatus may always be treated by quantum mechanics, and be measured by a second apparatus which has such a dual description. This article examines whether these two different descriptions are mutually consistent. It is shown that if the dynamical variable used in the first apparatus is represented by an operator of the Weyl-Wigner type (for example, if it is a linear coordinate), then the conversion from quantum to classical terminology does not affect the final result. However, if the first apparatus encodes the measurement in a different type of operator (e.g., the phase operator), the two methods of calculation may give different results.Comment: 18 pages LaTeX (including one encapsulated PostScript figure

Collisional perturbation of radio-frequency E1 transitions in an atomic beam of dysprosium

We have studied collisional perturbations of radio-frequency (rf) electric-dipole (E1) transitions between the nearly degenerate opposite-parity levels in atomic dysprosium (Dy) in the presence of 10 to 80 $\mu$Torr of H$_\text{2}$, N$_\text{2}$, He, Ar, Ne, Kr, and Xe. Collisional broadening and shift of the resonance, as well as the attenuation of the signal amplitude are observed to be proportional to the foreign-gas density with the exception of H$_2$ and Ne, for which no shifts were observed. Corresponding rates and cross sections are presented. In addition, rates and cross sections for O$_2$ are extracted from measurements using air as foreign gas. The primary motivation for this study is the need for accurate determination of the shift rates, which are needed in a laboratory search for the temporal variation of the fine-structure constant [A. T. Nguyen, D. Budker, S. K. Lamoreaux, and J. R. Torgerson, Phys. Rev. A \textbf{69}, 22105 (2004)].Comment: 11 pages, 8 figure

Testing of quantum phase in matter wave optics

Various phase concepts may be treated as special cases of the maximum likelihood estimation. For example the discrete Fourier estimation that actually coincides with the operational phase of Noh, Fouge`res and Mandel is obtained for continuous Gaussian signals with phase modulated mean.Since signals in quantum theory are discrete, a prediction different from that given by the Gaussian hypothesis should be obtained as the best fit assuming a discrete Poissonian statistics of the signal. Although the Gaussian estimation gives a satisfactory approximation for fitting the phase distribution of almost any state the optimal phase estimation offers in certain cases a measurable better performance. This has been demonstrated in neutron--optical experiment.Comment: 8 pages, 4 figure

Implementing Unitarity in Perturbation Theory

Unitarity cannot be perserved order by order in ordinary perturbation theory because the constraint UU^\dagger=\1 is nonlinear. However, the corresponding constraint for $K=\ln U$, being $K=-K^\dagger$, is linear so it can be maintained in every order in a perturbative expansion of $K$. The perturbative expansion of $K$ may be considered as a non-abelian generalization of the linked-cluster expansion in probability theory and in statistical mechanics, and possesses similar advantages resulting from separating the short-range correlations from long-range effects. This point is illustrated in two QCD examples, in which delicate cancellations encountered in summing Feynman diagrams of are avoided when they are calculated via the perturbative expansion of $K$. Applications to other problems are briefly discussed.Comment: to appear in Phys. Rev.